Newborn babies can develop yellowing of the skin and eyes known as jaundice. Most newborn jaundice is mild and clears without causing any harm. However, some babies have risk factors that mean their jaundice needs closer monitoring, rapid testing and, in some cases, emergency treatment.

Kernicterus can happen when a baby has very high bilirubin levels - hyperbilirubinaemia - that are not treated quickly enough. Bilirubin is a yellow substance made when red blood cells break down. If too much bilirubin builds up in a baby’s blood, it can cross into the brain and cause a serious brain injury. This is sometimes described as bilirubin encephalopathy. When the damage becomes permanent, it is known as kernicterus, or chronic bilirubin encephalopathy.

For parents, it is important to know that kernicterus is usually linked to severe jaundice that should have been recognised and treated. Doctors, midwives and nurses should know which babies have an increased risk, when bilirubin levels need to be checked, and when treatment such as phototherapy or an exchange transfusion is needed.

This guide explains the main risk factors for kernicterus, what good care should involve, and what options may be available if medical negligence played a part in your child’s injury.

What Are the Main Risk Factors for Kernicterus?

Recognising the risk factors of kernicterus should prompt doctors, midwives and nurses to take extra care. A baby with one or more risk factors may need closer observation, earlier bilirubin testing and clear safety-netting advice before going home.

A risk factor does not mean a baby will develop kernicterus. It means the care team should recognise that the baby may be more likely to develop neonatal jaundice and is therefore at increased risk of developing hyperbilirubinaemia and should act in line with NHS and NICE guidance.

The main risk factors include the following.

Premature birth

Babies born before 38 weeks have a higher risk of developing significant jaundice. This is because their liver may be less able to process bilirubin in the first days after birth.

A baby’s gestational age should be taken into account when doctors and midwives assess jaundice. Preterm infants may need closer checks because their bilirubin levels can rise quickly, and they may be more vulnerable to the effects of too much bilirubin.

Where a baby is premature, the care team should explain what parents need to watch for and arrange appropriate follow-up. If jaundice appears, bilirubin levels should be measured and reviewed against the correct treatment thresholds for the baby’s age and gestation.

Jaundice in the first 24 hours

Jaundice that appears in the first 24 hours of life should always be treated seriously. This is not the usual pattern of physiologic jaundice, which often appears a little later.

The NICE guideline on jaundice in newborn babies says that if a baby has suspected or obvious jaundice in the first 24 hours, their serum bilirubin should be measured urgently. This means doctors and midwives should not simply reassure parents or wait to see whether the jaundice improves.

Early jaundice can be linked to blood type incompatibility, haemolytic disease or other conditions that cause red blood cells to break down more quickly. This can lead to increased bilirubin production and a rapid rise in bilirubin levels.

A previous sibling who needed treatment for jaundice

If a baby’s older brother or sister needed treatment for neonatal jaundice, this is a recognised risk factor. It may suggest that there is a family pattern, an inherited condition or another shared factor that increases the chance of significant jaundice.

Doctors and midwives should ask about this after birth. If the family history is known, the baby should be monitored carefully and parents should be told what signs to look for once they leave hospital or the birth centre.

Breastfeeding exclusively 

Inadequate feeding in the first days after birth can increase bilirubin levels. This can happen when a baby is struggling to feed, not taking enough milk, losing weight or becoming dehydrated.

Breastfed newborns can develop jaundice while feeding is being established. This does not mean breastfeeding should stop, but it does mean that midwives, health visitors and doctors should take concerns seriously. They should check the baby’s feeding, weight, wet nappies and stools, and arrange bilirubin testing if jaundice is suspected. Where intake is poor, prompt feeding support and fluid supplementation may help.

Parents should be given clear advice about when to seek help. Poor feeding, unusual sleepiness and worsening yellowing of the baby’s skin or eyes should never be dismissed.

There is also a form of jaundice known as breast milk jaundice, which can last longer in some babies. This is usually harmless, but prolonged jaundice still needs proper assessment so that doctors can rule out other causes.

Blood group incompatibility

Blood group incompatibility can increase the risk of severe jaundice. This can happen when the mother and baby have different blood types and antibodies affect the baby’s red blood cells.

This includes rhesus disease and ABO incompatibility (otherwise known as haemolytic disease of the fetus and newborn [HDFN]). These conditions can cause haemolytic disease, an immune response where red blood cells break down more quickly than usual. When this happens, the baby’s blood may contain too much bilirubin, and bilirubin levels can rise quickly.

The NHS guide to HDFN explains how antibodies can affect a baby’s red blood cells. Where blood group incompatibility is known or suspected, doctors should check the baby carefully and arrange the right blood tests. This may include checking the baby’s blood type, reviewing neonatal blood samples and measuring total serum bilirubin.

If the care team fails to recognise blood type incompatibility, does not act on abnormal results or delays treatment, this may raise concerns about medical negligence.

G6PD deficiency, Gilbert’s syndrome, and other inherited blood conditions

G6PD deficiency is an inherited condition that can make red blood cells break down more easily. This can lead to increased bilirubin production and a higher risk of severe jaundice.

Other inherited blood conditions, such as Gilbert’s syndrome, can also affect how bilirubin is produced or cleared from the body. Some genetic disorders interfere with the baby’s liver and its ability to process bilirubin. Rare metabolic disorders can also increase the risk of neonatal hyperbilirubinaemia. 

These inherited conditions on their own should not cause hyperbilirubinaemia. However, when combined with other risk factors, such as breast milk jaundice or prematurity, they can result in neonatal hyperbilirubinaemia. 

These conditions may be more common in some family backgrounds. Doctors and midwives should take family history and ancestry into account when assessing a baby with jaundice. Where G6PD deficiency or another inherited condition is possible, further testing may be needed.

Bruising, cephalohaematoma or birth trauma

Some babies have bruising after birth, particularly if the birth was difficult or assisted. A cephalohaematoma is a collection of blood under the baby’s scalp. As the trapped blood breaks down, it can add more bilirubin to the baby’s system.

Severe birth trauma can therefore increase the chance of high bilirubin levels. This does not mean that every baby with bruising will develop severe jaundice, but it should alert doctors and midwives to the need for careful checks.

If a baby has visible bruising, swelling to the head or signs of birth trauma, the care team should monitor for jaundice and measure bilirubin levels where needed.

Infection or a baby being unwell

A baby who is unwell may be at increased risk from jaundice. Infection, breathing problems, poor feeding and other signs of illness can affect how the body handles bilirubin.

In some babies, illness may mean that the same bilirubin concentration carries more risk. This is sometimes described as low bilirubin kernicterus, where injury can occur even though the bilirubin level is not as high as might usually be expected.

This is why doctors and nurses should look at the whole picture, not just one test result. They should consider the baby’s age, gestational age, feeding, weight, general condition and whether bilirubin levels are rising.

Other risk factors

Other risk factors may include:

• A family history of jaundice
• Male infants, who may have a higher chance of raised bilirubin levels than female infants
• Extremely low birth weight
• Neonatal polycythaemia, where a baby has a high number of red blood cells
• Liver disease
• Rare genetic conditions that affect the body’s ability to conjugate bilirubin

Some of these factors are uncommon. However, they all point to the same principle: where a baby has a higher risk of severe jaundice, doctors, midwives and nurses should monitor them carefully, measure bilirubin levels at the right time and act quickly if treatment is needed.

For more detail on how these problems can lead to serious jaundice, read our guide to the causes of kernicterus in newborn babies.

What Should Doctors and Midwives Do When a Baby Has Risk Factors?

When a baby has risk factors for kernicterus, doctors, midwives and nurses should take steps to reduce the chance of neonatal jaundice becoming dangerous. This starts with recognising which babies need closer monitoring, then measuring bilirubin levels at the right time and arranging treatment when needed.

Parents should not be expected to work this out alone. Parents should be provided information tailored to their needs. NICE states that information should include:

• Factors that influence the development of significant hyperbilirubinaemia
• How to check the baby for jaundice
• What to do if they suspect jaundice
• The importance of recognising jaundice in the first 24 hours and of seeking urgent medical advice
• The importance of checking the baby's nappies for dark urine or pale chalky stools
• The fact that neonatal jaundice is common, and reassurance that it is usually transient and harmless
• Reassurance that breastfeeding can usually continue

Check for jaundice before and after discharge

Doctors, midwives and nurses should check babies for jaundice in the first few days after birth. This is especially important in the first 72 hours, when bilirubin levels can rise.

Jaundice may be seen as yellowing of the baby’s skin or the whites of their eyes. However, it can be harder to spot by looking alone, especially in babies with darker skin. For this reason, the baby should be examined naked in bright and preferably natural light. The baby’s gums should be assessed and the examiner should press lightly on their skin to check for signs of jaundice in “blanched” skin.

If a baby has recognised risk factors, the care team should be more alert to the possibility of severe jaundice. This may include arranging further checks after discharge, making sure parents understand the warning signs, and explaining who to contact if the baby becomes more yellow, sleepy or difficult to feed.

Measure total serum bilirubin levels when jaundice is suspected

If jaundice is suspected, doctors and midwives should measure the baby’s bilirubin levels. They should not simply reassure parents without carrying out the right checks.

Bilirubin may be measured using a skin device called a transcutaneous bilirubin meter, or through a blood test to measure serum bilirubin. In some situations, a blood test is needed straight away. For example, if jaundice appears in the first 24 hours of life, the baby’s serum bilirubin should be measured urgently.

The result should be assessed against the baby’s age in hours and gestational age. This matters because a bilirubin level that is safe for one baby may be more concerning for another, especially if the baby was born early or is unwell.

Act quickly if bilirubin levels are high

Where bilirubin levels are too high, treatment should begin promptly. The main treatment for neonatal jaundice is phototherapy, where the baby is placed under a special blue light that helps the body break down bilirubin.

If phototherapy is not enough, or if the baby’s bilirubin levels are dangerously high, doctors may need to consider an exchange transfusion. This is a more intensive treatment that removes bilirubin from the baby’s blood quickly. Phototherapy and exchange transfusion are both used to reduce the risk of acute bilirubin encephalopathy and prevent permanent injury.

Delays in providing treatment can result in a missed opportunity to intervene before brain damage occurs. 

Listen to parents’ concerns

Parents are often the first people to notice that something has changed. They may see that their baby looks more yellow, is not waking for feeds, has fewer wet nappies, has a high-pitched cry or seems unusually floppy or stiff.

These concerns should be taken seriously. If a parent raises concerns about jaundice, feeding or their baby’s behaviour, a midwife, health visitor, GP or hospital doctor should assess the baby properly. Reassurance should be based on appropriate checks, not assumptions.

Medical negligence may be a concern if clear warning signs were dismissed, bilirubin levels were not measured, results were not acted on, or parents were sent home without the advice they needed.

Give clear safety-netting advice

Before a baby goes home, parents should be told what signs to look for and when to seek help. This is sometimes called safety-netting advice.

This advice should be clear and practical. Parents should know who to contact if their baby becomes more jaundiced, is not feeding well, is unusually sleepy, has fewer wet or dirty nappies, or develops worrying symptoms. They should also understand that jaundice in the first 24 hours, or jaundice that is getting worse, needs medical attention. 

Medical negligence may be a concern if parents and carers are not given adequate safety netting information. 

What Are the Early Signs Parents Should Watch For?

Parents should always seek medical advice if they are worried about their baby’s jaundice or behaviour. Most newborn jaundice is not harmful, but early diagnosis matters because severe jaundice can become dangerous if bilirubin levels continue to rise.

The NHS guide to jaundice in babies gives parent-facing information on the signs of jaundice and when to get help. If a baby appears unwell, is difficult to wake, is not feeding or has unusual movements, parents should seek urgent medical attention.

Signs of newborn jaundice

The most common sign of newborn jaundice is yellowing of the skin or the whites of the eyes. It may also be seen in the gums or inside the mouth.

Parents may notice that:

• The baby’s skin looks yellow
• The whites of the eyes look yellow
• The yellowing spreads (to other parts of the body, i.e. the trunk) or becomes more obvious (e.g. deepens)
• The baby is not feeding as well as expected, they become uninterested and do not take as much
• The baby has fewer wet or dirty nappies
• The baby seems unusually sleepy

These signs do not always mean a baby is developing kernicterus. However, they should prompt proper assessment, especially if the baby has risk factors such as premature birth, poor feeding, bruising, blood group incompatibility or jaundice in the first 24 hours.

Signs that jaundice may be becoming serious

If bilirubin levels become very high, a baby may show signs of acute bilirubin encephalopathy. This is the stage where too much bilirubin is starting to affect the brain, resulting in bilirubin-induced neurologic dysfunction. It requires urgent medical attention.

Warning signs may include:

• Poor feeding or refusing feeds
• Unusual sleepiness or difficulty waking
• A high-pitched cry
• Floppy muscles
• Stiffness or arching of the back
• Unusual eye movements
• Seizures or unusual movements
• Breathing problems or signs that the baby is very unwell

These symptoms can be frightening for parents. If they appear, the baby should be assessed urgently by a doctor, as they represent clinical manifestations of potentially serious health issues. Bilirubin levels should be checked and treatment should be arranged where needed.

For a fuller explanation of the signs to look out for, read our guide to the key symptoms of kernicterus every parent should know.

Why early action matters

Concerns about jaundice should never be dismissed without proper checks. If a baby has visible jaundice, is feeding poorly or seems unusually sleepy, doctors and midwives should consider whether testing is needed to see how much bilirubin is in their bloodstream, and if treatment is therefore needed.

Parents should not be made to feel that they are overreacting. Jaundice is common, but severe jaundice needs prompt attention. Where warning signs are missed and a baby develops kernicterus, families may have questions about whether medical negligence played a part.

When Can Kernicterus Be Linked to Medical Negligence?

Kernicterus may be linked to medical negligence if a baby’s risk factors, jaundice symptoms or rising bilirubin levels were not recognised and acted on in time.

Neonatal jaundice is common, but doctors, midwives, nurses, GPs and health visitors should know when it needs closer attention. This is especially important if jaundice appears in the first 24 hours, the baby was born prematurely, is feeding poorly, has blood group incompatibility, has bruising from birth trauma or appears unusually sleepy.

Concerns about medical negligence may arise where:

• Bilirubin levels were not measured when jaundice was visible or suspected
• Urgent serum bilirubin testing was not arranged for jaundice in the first 24 hours
• Known risk factors were missed or not acted on
• Parents were reassured without proper checks
• Poor feeding, dehydration or unusual sleepiness were dismissed
• Phototherapy was delayed or not monitored properly
• An exchange transfusion was not considered when bilirubin levels were dangerously high
• Signs of acute bilirubin encephalopathy were not treated as urgent

The key question is whether the care team responded properly to the baby’s condition. Where delayed testing or delayed treatment has allowed too much bilirubin to build up, kernicterus can be the result.

What Options Do Families Have If Their Child Developed Kernicterus?

If your child developed kernicterus, you may want to understand whether their jaundice should have been recognised or treated sooner. A birth injury claim can help families seek answers and, where the evidence supports it, secure compensation for the child’s long-term needs.

JMW can investigate what happened by reviewing maternity, neonatal, community midwifery, GP and hospital records. These records can show when jaundice was first noted, whether risk factors were present, whether bilirubin levels were measured and whether treatment started quickly enough. Parents’ own accounts are also important, especially where they raised concerns about feeding, sleepiness, yellowing of the baby’s skin or changes in behaviour.

Where needed, independent medical experts can advise on whether doctors, midwives or nurses provided a reasonable standard of care, and whether any delay caused or worsened the injury.

Compensation may help with the practical impact of kernicterus, including:

• Care and support at home
• Physiotherapy, occupational therapy and speech and language therapy
• Specialist equipment
• Mobility and communication support
• Adaptations to the family home
• Education support
• Transportation needs 
• Future needs into adulthood

For children, a parent or another suitable adult can usually bring a claim on their behalf before they turn 18. Once the child turns 18, they usually have until their 21st birthday to start a claim. Different rules may apply if the child does not have mental capacity as an adult.